Quick Review Questions

Question 1

what are the major divisons of the nervous system

Answer 1

Central and peripheral

Question 2

what organs make up the central nervous system

Answer 2

Brain and spinal cord.

Question 3

what are the five main types of glia

Answer 3

Astrocytes, microglia, ependymal cells, oligondendrocytes, and Schwann cells.

Question 4

what is neurilemma

Answer 4

The neurilemma is a nerve sheath formed as each Schwann cell wraps around the nerve fiber, and its nucleus and cytoplasm are squeezed to the perimeter.

Question 5

what are the three layers of connective tissues that hold the fibers of a nerve together

Answer 5

Endoneurium, perineurium, and epineurium.

Question 6

under what circumstance can a nerve fiber be repaired

Answer 6

Nerve fibers can sometimes be repaired if damage is not extensive, when the cell body and neurilemma remain intact and scarring has not occurred.

Question 7

what is the difference between white and gray matter

Answer 7

White matter is made up of myelinated fibers. Cell bodies and unmyelinated fibers make up the gray matter.

Question 8

what is meant by the threshold potential

Answer 8

The threshold potential occurs when the magnitude of the local depolarization surpasses a limit (typically -59 mV).

Question 9

how does temporal summation differ from spatial summation

Answer 9

Spatial summation is when the sum of the local potential reaches the threshold potential, causing voltage-gated channels in the axon membrane to open, thus producing an action potential. Temporal summation is when synaptic knobs stimulate a postsynaptic neuron in rapid succession, and their effects can add up over a brief period of time to produce an action potential.

Question 10

what is a reflex arc

Answer 10

A reflex arc is a signal conduction route to and from the central nervous system. Afferent (sensory) neurons conduct signals to the CNS from sensory receptors in the PNS. Efferent (motor) neurons conduct signals from the CNS to effectors. Interneurons conduct signals from afferent neurons toward or to motor neurons. Simpler reflex arcs do not have interneurons.

Question 11

what are the three coverings of the central nervous system

Answer 11

Dura mater, arachnoid membrane, and pia mater.

Question 12

what are the three major parts of the brainstem, and breifly describe the function

Answer 12

Medulla oblongata: Nuclei in the medulla contain a number of reflex centers (cardiac, vasomotor, and respiratory centers). Pons: contains the pneumotaxic centers that help regulate respiration. Midbrain: contains reflex centers for certain cranial reflexes (pupillary reflexes and eye movements).

Question 13

what are gyri and folia What are sulci?

Answer 13

Gyri are raised areas on the surface of both the cerebellum and the cerebrum. Sulci are grooves located on the surface of both the cerebellum and cerebrum

Question 14

name the five lobes that make up each cerebral hemisphere? where is each located?

Answer 14

The frontal, parietal, temporal, and occipital lobes are named for the bones that lie over them.The insula lies hidden from view in the lateral fissure.

Question 15

name the basal nuclei and describe where they are located within the cerebrum

Answer 15

Caudate nucleus, lentiform nucleus, and amygdaloid nucleus. They are located as “islands” of gray matter deep inside the white matter of each hemisphere.

Question 16

how are steriods able to pass through a cells plasma easily

Answer 16

. Steroids are lipid soluble; thus they can easily pass through the phospholipid plasma membrane of target cells.

Question 17

name some of the different general types of nonsteriod hormones. give an example of each

Answer 17

. Protein hormones: insulin, parathyroid hormones, growth hormone, prolactin, calcitonin, adrenocorticotropic hormone, and glucagon. Peptide hormones: oxytocin, antidiuretic hormone, MSH, somatostatin, thyrotropin-releasing hormone, GnRH, and ANH. Glycoproteins: FSH, LH, TSH, and CG. Amino acid derivative hormones: amine hormones (melatonin, epinephrine, and norepinephrine), iodinated amino acid hormones (thyroxine and triiodothyronine).

Question 18

why is the concept of nonsteriod hormone action often called the second messenger model? why is it known as the fixed membrane receptor model?

Answer 18

A nonsteroid hormone molecule acts as a “first messenger,” delivering its chemical message to fixed receptors in the target cell’s plasma membrane. The “message” is then passed into the cell where a “second messenger” triggers the appropriate cellular changes.

Question 19

names some ways that the secretion of an endocrine cell can be controlled

Answer 19

Negative feedback and positive feedback loops. The simplest mechanism operates when an endocrine cell is sensitive to the physiological changes produced by its target cells. Another mechanism that may influence the secretion of hormones by a gland is input from the nervous system.

Question 20

why are prostaglandins sometimes called tissue hormones

Answer 20

term tissue hormone is appropriate because the secretion is produced in a tissue and diffuses only a short distance to other cells within the same tissue

Question 21

what are the two main divisions of the pituitary called? how are they distinguised by location and histology

Answer 21

Adenohypophysis and neurohypophysis. The adenohypophysis is anterior and develops from any upward projection of the pharynx and is composed of regular endocrine tissue. The neurohypophysis is posterior and develops from a downward projection of the brain and is composed of neurosecretory tissue.

Question 22

name the two hormones of the neurpophysis

Answer 22

. Antidiuretic hormone and oxytocin.

Question 23

how does the pineal gland adjusts to the biological clock

Answer 23

Visual signals received by the pineal gland allow it to determine day length and lunar cycles.

Question 24

where is the thyroid located? what does it look like

Answer 24

The thyroid is located in the neck, on the anterior and lateral surfaces of the trachea, just below the larynx. Butterfly.

Question 25

how do calcitonin and parathyroid hormone act together to regulate homeostasis of blood calcium concentration

Answer 25

Calcitonin apparently controls calcium content of the blood by increasing bone formation by osteoblasts and inhibiting bone breakdown by osteoclasts. Calcitonin tends to decrease blood calcium levels and promote conservation of hard bone matrix. Parathyroid hormone is an antagonist to calcitonin because it has the opposite effects.

Question 26

name some effects of cortisol in the body

Answer 26

Answers may include: Glucocorticoids (cortisol) accelerate the breakdown of proteins into amino acids, tend to accelerate mobilization of both lipids from adipose cells and lipid catabolism by nearly every cell in the body, and are essential for maintaining normal blood pressure. High blood concentration of glucocorticoids causes a marked decrease in the number of white blood cells. Normal amounts of glucocorticoids act with epinephrine to bring about normal recovery from injury produced by inflammatory agents. Glucocorticoid secretion increases as part of the stress response, and, except during the stress response, glucocorticoid secretion is controlled mainly by means of a negative feedback mechanism.

Question 27

name two of the four principal hormones secreted in the pancreatic islets

Answer 27

Glucagon, insulin, somatostatin, and pancreatic polypeptide

Question 28

in what way do insulin and glucagon exert antagonistic influences on the concentration of glucose in the blood

Answer 28

Glucagon tends to increase blood glucose levels by stimulating the conversion of glycogen to glucose in liver cells. Insulin tends to promote the movement of glucose out of the blood and into tissue cells.

Question 29

what are the major hormones secreted by reproductive tissues (gonads and the placenta)

Answer 29

Testosterone, estrogen, progesterone, and human chorionic gonadotropin